Tools of the Trade

Information

A hammer and a saw used to be the key tools for home contractors. Today, the best-in-breed also use high-tech equipment while performing a professional energy audit or verifying that construction has been done correctly.

Comment Wall

You need to be a member of Tools of the Trade to add comments!

Ladies and Gentlemen, I have to tell ya, I'm a HUGE fan of flexible probes! Love my flexible probe for my Testo 327 - NO more drilling!! and, the flexible, lighted probe on my video boroscope is awesome! Today, I saw what was happening under a dryer - solved a combustion air issue by cleaning!

First, the flow rings are always attached on the inlet side of the fan, regardless of whether you pressurizing or depressurizing. Admittedly, this does make it less convenient to change the rings if that becomes needed, since you'll have to remove the flex duct first.

The ability to test in either direction, however, is a key feature of the Retrotec DucTester. It is true, Ron, that if the grill mask holds tight, there should be very little difference in the results between depressurization and pressurization, however, the possibility does exist that if it's not properly secured, the grill mask can be pushed off a register, leading to faulty results, or a repeated test. Hence our recommendation. However, it must be clearly said that if there's a risk of polluted, dusty, or mouldy air being pulled into the house, the ducts do not need to be depressurized.

We are using flexible probes for our combustion analyzers. Great solution for checking undiluted flue gasses for CO content. Instead of drilling holes in draft diverters in order to get the probe into the undiluted gasses, we use flexible probe. Check out the photos I've uploaded.

Thanks for that. I've been curios since you raised the topic if there would be a difference. I'll try it some time with my Energy Conservatory Duct Blaster and if I see anything funny I'll let you know.

Ron - As far as running the Retrotec duct tester either way, after your question, I was teaching a class yesterday, and we ran the duct tester both ways and got exactly the same result. It was extremely handy to be able to leave the blower door installed to quickly do the Total Pressure and then the Pressure to outside. (The ducts in the building I was testing were awful to say the least. Even the theatrical smoke was diluted to the extent that it was hard to see.)

I have been using a Motion Computing J3500 for auditing. It's built for field work with "Gorilla" glass and a solid state drive. It is not cheap, but it's incredibly fast and extremely bright even in direct sunlight. It takes a little getting used to - carrying this amazing machine in an attic or crawl space. It takes pictures and even can serve as a telephone.

I have been playing with HomeGauge software. It is designed primarily for Home Inspectors, but it does have an energy template. I am working with them to refine the output, but it has a spreadsheet for BPI combustion safety testing, etc. I like the idea that it is on my computer and I don't have to pay annual fees or individual use fees or any other fees. I haven't done it yet, but they can take your data on-line so that your clients can download it. It's really easy to add pictures and they have an enormous bucket full of pre-written comments like warnings about windows not being the first step in saving energy. It does figure area weighted R values and the BAS as well.

The first report I did was about 35 pages long, which is very fancy, but too much information for the average homeowner.

I don't think Retrotec's argument holds much water. Have they tested a hundred house systems both ways, pressurized and then depressurized, and measured the difference? I can't imagine it would be enough to impact my recommendations to a homeowner. I'm not giving you a hard time, it's just that this is the first time I've heard depressurizing ducts suggested, so the possibilities are intriguing. Have you done it?

That certainly may happen. Retrotec advises depressurizing so that the duct masks are pulled more tightly against the grilles rather than being pushed off. Also, if a "Leakage to Outside" test is going to be done using the blower door, the blower door fan doesn't have to be turned around to blow air into the house. And if it is a cold winter day, blowing 25 Pa of outside air into the house may be more detrimental than some leakage from the crawl space.